LONDON -- If Arsenal had kept 10 men on the pitch; if Mesut Ozil hadn't missed a penalty; if Arsenal could have maintained the energy it showed in the first half, perhaps it might have been different.
When Wojciech Szczesny - justifiably - collected the 100th red card Arsenal has suffered under Arsene Wenger eight minutes before halftime, a fascinating contest became a game of attack against defense. By one careless challenge was Arsenal's Champions League campaign ended. It can take great credit from the way it played in the opening 37 minutes, but it is almost certainly out after a 2-0 home loss to Bayern Munich.
Other clubs, though, may draw encouragement. Bayern, it turned out, could be rattled. The two central defenders, Jerome Boateng and Dante, never looked comfortable against the energy of Yaya Sanogo, surprisingly selected ahead of Olivier Giroud, and for a time, Arsenal's intensity, the determined verticality of much of its play, was a genuine threat.
But when the opportunity came to draw first blood, to turn potential into a goal, Arsenal spurned it. Jack Wilshere, who had begun the game superbly, nutmegged Javi Martinez and laid in Mesut Ozil. As he turned inside, he tumbled over Boateng's legs. Without Mikel Arteta, Arsenal's usual penalty taker, responsibility fell on Ozil and, nervousness written across his face, he clipped his attempt straight down the middle, allowing Manuel Neuer to beat the ball away.
"I prefer players who run properly at the ball," Arsenal manager Arsene Wenger said. "It affected him."
Ozil almost visibly crumpled. A couple of minutes later, he could still be seen berating himself, and confidence seemed to desert him. For the rest of the game, his touch was uncertain, his passing wayward, he stopped looking for the ball; it was slightly baffling that when forced to make a substitution to introduce Lukasz Fabianski, it was Santi Cazorla rather than he who was withdrawn.
Yet Arsenal continued to trouble Bayern and, while it would be misleading to suggest it was dominating, it at least matched Bayern. That that is considered an achievement, though, suggests just how good this Bayern unit is. All through that opening 37 minutes, as Arsenal created chances, so too did Bayern. Szczesny had been called into a stretching save up and to his left as early as the third minute to keep out a Toni Kroos drive towards the top corner and there had been a number of moments when it took desperate blocks to keep Bayern out.
It was Kroos, who completed the same number of passes as every Arsenal outfield player put together, who conjured the key moment of the game as his chip set Arjen Robben through (amid all the talk of the red card changing the game, it should be remembered it was induced by the quality of Bayern's play).
His first touch took him wide of Szczesny, at which the goalkeeper clattered into his standing leg. That it was a penalty was clear and while it could have been argued that Robben would not have reached the loose ball to turn it in, there's no real arguing against the red card that followed. Arsenal, like Manchester City on Tuesday, found itself a man down and facing a penalty as the result of one poor challenge, a rule that the International Board looks likely to recommend changing for next season when it meets on March 1.
Fabianski, such a key figure on the win over Liverpool on Sunday came on with the chance of becoming an instant hero. He didn't need to be: he threw himself the wrong way, but David Alaba's penalty struck the base of the post. The respite was brief. Playing against Bayern with 11 men is difficult enough; with only 10 is all but impossible.
Arsenal was reduced to sitting two banks of four behind the ball, looping long clearances towards Sanogo, whose night became increasing fruitless, particularly after Boateng had been removed for Rafinha, allowing Phillip Lahm to move into midfield as Javi Martinez dropped back.
"It doesn't just change the game," Wenger said of the red card. "It kills the game. The game was until then top quality and in the second half it was maybe for neutral people boring because it was one-way traffic. It was a great football game until halftime and it was no game at all after halftime."
Slowly the rhythm built, the long skeins of passes swept across the pitch, always probing for space until the breakthrough at last arrived nine minutes into the second half. Robben laid a pass inside to Kroos who, under pressure from Flamini, rolled it back out to Lahm who, seeing Flamini gad dropped back, rolled it again to Kroos, who swept a brilliant curling sidefooter into the top corner.
From then on it was simply a matter of how many. Fabianski saved a low volley from Robben, who then hit a low curler just wide and Mario Gotze had a header deflected off target by Per Mertesacker. The second did arrive, but not until the 88th minute, with substitute Thomas Muller, having wandered away from Flamini, heading in Lahm's cross as Arsenal was caught on the break having sent men forward for a free kick.
Last time Arsenal went to the Allianz Arena, it won 2-0 to go out on away goals. This time, that scoreline would at least force extra time, but it's hard to imagine Bayern being as sloppy this time as it was then. Its march goes on.